Expandable brachytherapy device

ABSTRACT

A brachytherapy device for the provision of brachytherapy is disclosed. The brachytherapy device has at least one source lumen located outside a movable surface of the device. The source lumen may be secured to the movable outer surface in a manner whereby relative movement of the source lumen relative to the movable outer surface is permitted. The brachytherapy device is inserted into a body cavity. After insertion, the movable surface is moved to position the at least one source lumen closer to the tissue boundary of the cavity. One or more sources of radiation are then placed within the at least one source lumen to provide a customizable treatment. Also disclosed are methods for providing brachytherapy via body cavities.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. patent application Ser. No.11/266,994, filed on Nov. 4, 2005, pursuant to 35 U.S.C. § 120, which,in turn, claims the benefit of U.S. provisional patent application No.60/625,355, filed on Nov. 5, 2004, pursuant to 35 U.S.C. § 119(e), thetexts of which are hereby incorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to the field of brachytherapy. In particular theinvention relates to an expandable brachytherapy device and methods ofusing it with the ability to provide a tailored radioactive doseprofile.

2. Description of the Related Technology

A variety of devices exist for performing brachytherapy on the body.Exemplary devices that are employed in body cavities or cavities createdin the body by surgery include, for example, brachytherapy devices fortreatment of breast cancer, uterine cancer, prostate cancer, treatmentof a cavity left by removal of a tumor, cyst, polyp or similar mass, andtreatment or prevention of restenosis. Some of these devices are merelyimplants that are implanted in a cavity in the body to deliver thetreatment. However, certain types of devices are expandable to allowinsertion of the device into the body in an unexpanded state, andsubsequent expansion of the device to deliver the brachytherapy. Suchexpandable devices are particularly useful for the treatment of, forexample, breast cancer, vascular restenosis and uterine cancer.

Breast cancer affects many women. Not only is breast cancer a seriousand life threatening illness, quite frequently the methods involved intreating breast cancer can have dramatic life altering cosmeticramifications for a woman. Treatments, such as mastectomies, involveradical surgical procedures that while saving a patient's life,oftentimes extract a high price on both the physical and mental healthof a patient. Other treatment methods may be preferable because of thesedrawbacks.

One method of treating breast cancer is by subjecting a cancerous tumorto radiation treatment. Although, doing this can be as effective incuring breast cancer as more radical procedures, there is a chance thatthe intense radiation used in destroying the cancer can adversely affecthealthy tissue in the area surrounding the area treated. One method foravoiding potential damage to healthy tissue is through the use ofspecial brachytherapy treatment procedures. Applying radiation treatmentaccording to a specialized treatment plan may permit a more effectivetreatment while minimizing undesirable consequences of that treatment.

In a patient with breast cancer one method of treating the cancer is toexcise the tumor without removal of the entire breast. Excising thetumor is performed in a procedure called a lumpectomy. A lumpectomy isthe surgical removal of a tumor in the breast, along with a small marginof the surrounding normal breast tissue. A lumpectomy may also be calleda wide excision biopsy, breast conserving therapy or quadrantectomy(this latter term is used when up to one fourth of the breast isremoved). The procedure is often performed on women with small orlocalized breast cancers and can be an attractive surgical treatmentoption for breast cancer because it allows women to maintain most oftheir breast after surgery. Several studies have shown that women withsmall breast tumors have an equal chance of surviving breast cancerregardless of whether they have a lumpectomy, followed by a full courseof radiation therapy, or mastectomy (complete breast removal, whichgenerally does not require post-operative radiation treatment). Alumpectomy may be performed using a local anesthetic, sedation, orgeneral anesthesia, depending on the extent of the surgery needed. Thesurgeon makes a small incision over or near the breast tumor and excisesthe lump or abnormality along with a margin of an appropriate thicknessof normal surrounding breast tissue.

Upon excision of the tumor, a cavity is created in the space where thetumor once existed, however some cancerous tissue may remain at themargins. In order to ensure a full recovery, radiation therapy isapplied in the area where the tumor was located. An exemplary method forperforming radiation therapy is to employ an expandable brachytherapydevice that has been inserted into the cavity that remains after thelumpectomy.

One method for using brachytherapy to treat breast cancer involvesplacing a radioactive source within a balloon catheter that has beeninserted into the cavity formed by the lumpectomy. The radioactivesource is placed within the central lumen of the balloon catheter, whichis generally centered on the longitudinal axis of the expanded device.This practice places significant limitations on the ability to customizethe treatment for a particular patient. For example, placing theradioactive source within the central lumen of the balloon does notpermit the radioactive dosage to be tailored to treat primarily only theareas surrounding the cavity that require irradiation. Also, placementof the radioactive source in the central lumen may result in healthytissue being exposed to undesirable amounts of radiation during exposureof the tissue requiring treatment and/or underexposure of tissue that isa high risk for cancer recurrence. This is at least partially due to thefact that the cavity created by the lumpectomy is generally non-uniformin shape, thereby creating a situation where the distance from thecentral lumen to tissue at the edge of the cavity may vary at differentlocations in the cavity, or healthy tissue is located in the treatmentregion of the radiation field. This is also partially due to the factthat healthy tissue may be located closer to the central lumen at somelocations than at other locations. This means that in the interest ofpreserving healthy tissue and minimizing dose to the skin, the physicianmay have to use a dose distribution that is less effective than desired.Alternatively, should the physician employ a dose sufficient to ensureeffective treatment, healthy tissue may be damaged. As a result, manyphysicians opt for alternative treatments to avoid the risks associatedwith the prior art devices.

The catheter material must be stiff enough to maintain structural andfunctional integrity and flexible enough to minimize discomfort and thechance of injury. A broad range of technical properties (modulus ofelasticity, apparent flexural modulus, and durometer) can be achieved byusing variations on the thousands of different resins that are currentcommercially available. The catheters are typically constructed of manydifferent materials such as: polyvinyl chloride (PVC), polyethylene(PE), polyolefin copolymer (POC), nitinol, fluoropolymers, polyurethane(PU), polyetheretherketone (PEEK), polyimide, polyethylene terephthalate(PET), super-elastics, and shape memory materials. The materials usedmay also be rendered radio-opaque by the loading of additives such asbarium sulfate.

Some prior art brachytherapy methods using balloon catheters to deliverthe radioactive source are discussed below.

An article by Paul V. Harper from 1966, entitled “Some TherapeuticApplications of Radioisotopes,” published in the Journal MSMA, discussesuse of balloon catheters for the treatment of cancer. Harper describes awater filled balloon provided with a central glass tube which can beused to fill the balloon. A radioactive tantalum wire is inserted intothe central glass tube once the balloon is located at the treatment areaand inflated in order to provide brachytherapy to the treatment area.The Harper device provides an isodose curve that is substantially thesame shape as the inflated balloon surface of the device. Harper alsodescribes filling a specially-designed catheter with a liquid solutionof radioisotope after the catheter has been inserted into the body inorder to provide radiation to the treatment area. In addition, Harperdescribes the provision of plastic spheroids coated with a radioactivematerial, which may be packed into a cavity in the body for delivery ofa brachytherapy treatment.

Another method for interstitial brachytherapy involves the insertion ofa plurality of hollow needles or catheters into the breast and throughthe surgical cavity in the breast, followed by placement of radioactivesources in the needles according to a predetermined treatment plan. Highdose rate iridium sources as well as seed strands are examples of thetype of radiation sources that may be employed in this type ofinterstitial brachytherapy.

U.S. Pat. No. 6,482,142 to Winkler et al. discloses a catheter for usein a method for interstitial brachytherapy in a tumor bed. Winklerdiscloses a device, shown in FIG. 4, having a radiation source 82 madeof three wires 84, 86, and 88, each having a plurality of radiationparticles. Wire 86 is a straight wire that extends along the axis of thedevice and wires 84 and 88 are curved wires that may be made from ashape memory material to allow deformation of the wires for insertionand removal from the catheter. More or fewer wires can be provided.

U.S. Pat. No. 5,302,168 to Hess discloses using a balloon catheter forthe treatment of restenosis. FIGS. 2-4 show a balloon 36 withradioactive elements 38 attached to the outer surface thereof.Alternatively, the surface of the balloon may be coated with radioactivematerial. It appears from FIG. 4, that the radioactive elements 38expand from a first size, shown in FIG. 2, to a second, larger size,shown in FIG. 4, as the balloon 36 expands.

U.S. Pat. No. 5,863,284 to Klein discloses a balloon catheter for use inangioplasty. Radioactive sources 30 are spaced around the circumferenceof the balloon. The sources may be attached to the balloon (FIGS. 4 and4a) or may be contained in a sleeve 48 designed to fit over the balloon(FIGS. 9-10). At col. 13, lines 1-30, a distal portion 18 includes aplurality of slits to allow expansion of distal portion 18 when theballoon is inflated to thereby position radioactive elements 30 atsubstantially uniform intervals around the inflated balloon. At col. 14,lines 46+, a device is described wherein the distal portion 18 includesan elastomeric expansible region 38 which allows expansion of the distalportion 18 when the balloon is expanded to maintain equal spacing of theradioactive elements about the circumference of the balloon. In theembodiment of FIGS. 7-8 described at col. 15, lines 5-19, the distalportion 18 includes a plurality of folds which allow expansion of thedistal portion when the balloon is inflated. At col. 15, lines 20-25,the embodiment shown in FIGS. 9-10 is described. In this embodiment, asleeve 48 containing a plurality of folds is fitted over the balloon.The sleeve 48 is expandable by virtue of the folds when the balloon isexpanded. In yet another embodiment, the radioactive element isintegrally formed with the balloon such that the radioactive elementmoves with the balloon as the balloon is expanded. To improve theuniformity of the radiation dose, the device may employ a secondaryradiation source in the form of a guide wire inserted into the centrallumen of the balloon catheter.

The devices discussed above offer various methods for using a ballooncatheter in brachytherapy, but do not address the provision ofcustomized dosing which can be achieved through the use of certainadvantageous features of the present invention discussed below and setout in detail in the detailed description of the preferred embodiments.It is an object of certain embodiments of the invention to provide anapparatus and method for providing tailored brachytherapy treatment.

SUMMARY OF THE INVENTION

In a first aspect, the present invention relates to a brachytherapydevice. The device includes a movable surface portion. One or moresource lumens are situated outside the surface portion of the device andextend a distance sufficient to permit a radiation source to be loadedinto the one or more source lumens from outside the body after thedevice is positioned inside a body or surgical cavity for therapy. Oneor more sources of radiation may be placed within one or more of thesource lumens to provide a customized radiation dose to a treatmentarea. One advantage of the present invention is that the sources ofradiation may be placed at different locations along the length of eachsource lumen for the same or different time periods to allow forcustomization of the dose delivered to the treatment area.

In a second aspect, the present invention relates to a method ofproviding brachytherapy. The method involves the step of inserting abrachytherapy device into a body or surgical cavity. The brachytherapydevice has one or more source lumens located outside a movable surfaceportion of the device. The method further includes the steps of movingthe surface portion within the cavity and placing one or moreradioactive sources within at least one of the source lumens to providea customized radiation dose to a treatment area.

These and various other advantages and features of novelty thatcharacterize the invention are pointed out with particularity in theclaims annexed hereto and forming a part hereof. However, for a betterunderstanding of the invention, its advantages, and the objects obtainedby its use, reference should be made to the drawings which form afurther part hereof, and to the accompanying descriptive matter, inwhich there is illustrated and described a preferred embodiment of theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of an expanded device in accordance with afirst embodiment of the present invention.

FIG. 2 shows a cross-sectional view of the proximal portion of theexpanded device taken along line II-II of FIG. 1.

FIG. 3 shows the balloon catheter of FIGS. 1-2 located in a cavity of apatient.

FIG. 4 shows a side view of an alternative embodiment of an expandeddevice with the tubes attached to the movable surface portion.

FIG. 5 is a cross-sectional view taken along V-V of FIG. 4.

FIG. 6 shows a side view of an alternative embodiment of an expandabledevice with lumens attached only to proximal and distal portions of thedevice.

FIG. 7 shows a front view of a manifold for use in the device of theinvention.

FIG. 8A shows a side view of a cylinder in the unexpanded stated formedby a plurality surface portions hingedly attached to one another.

FIG. 8B shows the same side view of the cylinder of FIG. 8A in theexpanded state.

FIG. 8C shows a view of the proximal end of the cylinder of FIGS. 8A-8B.

FIG. 8D shows a conical expander for use in expansion of the device ofFIGS. 8A-8C.

FIG. 9 shows a side view of an expandable device provided with anattachment sleeve for attachment of the expander to the expandablesurface portion.

FIGS. 10A-10B show longitudinal cross-sectional views of one embodimentof the expandable device shown in FIG. 9 employing flexible rods toexpand the expandable surface portion, with FIG. 10A showing the devicein the unexpanded state and FIG. 10B showing the device in the expandedstate.

FIG. 11 shows a longitudinal cross-sectional view of another embodimentof the expandable device shown in FIG. 9 employing centrally locatedlinkage arms to expand the expandable surface portion.

FIG. 12 shows a longitudinal cross-sectional view of yet anotherembodiment of the expandable device shown in FIG. 9 employing linkagearms to expand the expandable surface portion.

FIG. 13 shows a side view of another embodiment of an expandable deviceprovided with internal expansion means to expand the expandable surfaceportion.

FIG. 14 shows a longitudinal cross-sectional view of one embodiment ofthe expandable device shown in FIG. 13 employing flexible rods to expandthe expandable surface portion.

FIG. 15 shows a longitudinal cross-sectional view of another embodimentof the expandable device shown in FIG. 13 employing a wire mesh to formthe expandable surface portion.

FIGS. 16A-16B show another embodiment of an expandable device whichemploys a shape memory material, in the unexpanded and expandedpositions, respectively.

FIG. 17A shows an isometric view of another embodiment of an expandabledevice in non-expanded position.

FIG. 17B shows a cross sectional view of the device shown in FIG. 17A.

FIG. 17C shows an isometric view of another embodiment of an expandabledevice in an expanded position.

FIG. 17D shows a cross section view of the expanded device shown in FIG.17C.

FIG. 18A shows an alternative embodiment of a mechanism for expanding adevice.

FIG. 18B shows the mechanism in FIG. 18A in an expanded position.

FIG. 19A shows an alternative embodiment of a mechanism for expanding adevice.

FIG. 19B shows a cross sectional view of the mechanism shown in FIG. 19A

FIG. 20 shows a schematic representation of a method for using abrachytherapy device in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

Referring now to the drawings, wherein like reference numerals designatecorresponding structure throughout the several views, and referring toFIG. 1, a side view of a first embodiment of the present invention isshown. In this first embodiment of the invention, a brachytherapy deviceis provided with an internal lumen and includes a surface portion thatis movable. One or more source lumens are situated outside the movablesurface portion of the device and extend a distance sufficient to permita radiation source to be loaded into the one or more source lumens fromoutside the body after the device is positioned in an existing bodycavity or surgical cavity created by a surgical procedure for therapy.Thus, the devices of the present invention are applicable to bothinterstitial and inter-cavital brachytherapy procedures. One or moresources of radiation may be placed within one or more of the internaland source lumens to provide a customized radiation dose to a treatmentarea.

In the first embodiment of the invention shown in FIG. 1, thebrachytherapy device is a balloon catheter 10 that includes a movablesurface portion 2 formed by the surface of a balloon 14. As shown inFIG. 1, balloon 14 of balloon catheter 10 is in the inflated state.Balloon catheter 10 has a proximal portion 4, and a distal portion 6.Proximal portion 4 is of sufficient length to extend from balloon 14 toa location outside the body when balloon 14 is positioned within asurgical or body cavity. Distal portion 6 provides a location forsecuring tubes 8, which define external source lumens 7, to ballooncatheter 10. Tubes 8 may be secured to proximal and distal portions 4, 6of balloon catheter 10 by any suitable means such as an adhesive, meltbonding, staples, clips, or other conventional securing mechanisms.Tubes 8 may also be formed integrally with one or both of proximal anddistal portions 4, 6 of balloon catheter 10. In yet another embodiment,Tubes 8 are slidably secured to one or both of proximal and distalportions 10 within a manifold 30, such as that shown in FIG. 7, whichforms part of one or both of proximal and distal portions 4, 6. In thismanner, slack in tubes 8 may be taken up by sliding movement of aportion of tubes 8 through manifold 30 as the movable surface portion 2moves. Manifold 30 may be provided at either the proximal portion 4 ordistal portion 6 of the device.

As shown in FIGS. 1-2, balloon catheter 10 is provided with a pluralityof external source lumens 7 defined by tubes 8 which are attached to theproximal and distal portions 4, 6 of balloon catheter 10, by a suitableattachment means. Tubes 8 may have any cross-sectional shape, such as,for example, round, oval, elliptical, square, rectangular, triangular,pentagonal, hexagonal, ribbed, etc. Preferred tubes 8 are round, oval orelliptical to avoid any corners or edges that might catch duringinsertion or retraction of the brachytherapy device into or out of thebody or surgical cavity, but may also employ strengthening ribs withrounded edges, if desired. Source lumens 7 may also have anycross-sectional shape, including at least round, oval, elliptical,square, rectangular, triangular, pentagonal, hexagonal, etc. Sourcelumens 7 are provided for the purpose of receiving one or more radiationsources for treatment of the patient. The brachytherapy device mayinclude any number of external source lumens 7, and may include, forexample, 1-source lumens 7, 2-14 20 source lumens 7, or, optionally,4-16 source lumens 7. Different treatment circumstances may dictate theuse of different numbers of source lumens 7 depending on, for example,the size of the surgical or body cavity, and the treatment plan. One ormore radiation sources may be inserted into each of source lumens 7 toprovide a customized treatment as described in greater detail below. Inorder to provide a predictable customized treatment, it is desirable toensure that tubes 8 are positioned in predetermined locations relativeto a reference location, such as the longitudinal axis of ballooncatheter 10, so that dose calculations are based on an accuraterepresentation of the location of source lumens 7 and hence theradiation sources inserted into source lumens 7.

In the embodiment of FIG. 1, tubes 8 are not attached to movable surfaceportion 2 of balloon 14, which allows tubes 8 to move relative tomovable surface portion 2 of balloon 14. This is a useful feature ofthis embodiment since it allows tubes 8 to conform to the shape ofmovable surface portion 2, when it is expanded, without substantialdeformation of source lumens 7 as a result of inflation of balloon 14.Tubes 8 may be secured to movable surface portion 2 by a suitablesecuring means such as tack bonding or using a loop 12. Loops 12 may beattached at any location on movable surface portion 2. As shown, loops12 are attached midway between proximal portion 4 and distal portion 6.Loops 12 are attached to movable surface portion 2 and each loop 12surrounds a tube 8 to retain tube 8 in close proximity to movablesurface portion 2 in the area of loop 12. Loops 12 are shown with aminimal length but loops 12 may also extend some length in the axialdirection. Contact between loop 12 and tube surface 16 of tube 8restricts the movement of tube 8 in a radial direction relative tomovable surface portion 2. Loops 12 may be attached to movable surfaceportion 2 by any suitable, conventional securing means. Loops 12 may bemade of either a rigid material or a flexible material, though loops 12,in the embodiment shown, are made from a semi-rigid or flexible materialthat is biocompatible since loops 12 will contact body tissue during useof the device.

By securing tubes 8 via loops 12 to movable surface portion 2, tubes 8are free to move in the axial direction relative to movable surfaceportion 2, which allows slack in tubes 8 to be taken up during inflationof balloon 14, thereby preventing substantial deformation of sourcelumens 7 as a result of movement of movable surface portion 2. Thelongitudinal axis of balloon catheter 10 runs from the center ofproximal portion 4 to the center of distal portion 6. Slack in tubes 8may be provided in a number of different ways. For example, the lengthof tubes 8 that extends from proximal portion 4 to distal portion 6 maybe selected to provide slack in that portion of tubes 8. In thatembodiment, tubes 8 are slidably secured at the proximal portion 4 andhave sufficient length between proximal portion 4 and distal portion 6to conform to the movable surface portion 2 when balloon 14 is in theinflated condition. In an alternative embodiment, instead of attachingtubes 8 to proximal portion 4, tubes 8 can be attached to a movableattachment location, which is associated with, or forms part of,proximal portion 4. In this manner, slack in tubes 8 can be providedoutside the body or surgical cavity instead of between proximal portion4 and distal portion 6, thereby resulting in a potential reduction inthe diameter of balloon catheter 10 that has to pass through theincision to be inserted into the body. In this embodiment, the movableattachment location may be located at the proximal portion 4 for slidingmovement in a direction substantially parallel to the longitudinal axisof the device. The slack can also be provided at the distal portion 6 ofthe device by providing the movable attachment portion at the distalportion 6 of the device. Another possibility is to pass the proximal endof tubes 8 through a manifold 30, such as that shown in FIG. 7, andallow tubes 8 to slide within manifold 30 in order to provide therequired slack. In another embodiment, tubes 8 are rigidly attached tomanifold 30 and manifold 30 is movable to provide the required slack.

A variety of different types of radiation sources may be employed. Anysuitable, conventional source may be employed. For example, a wiresource or a catheter-mounted source may be employed. Radioactive seedsmay be attached to a device suitable for advancement through lumens 7,18 for delivering the brachytherapy. Exemplary radiation sources thatmay be employed are described in U.S. Pat. Nos. 5,199,939 and 4,282,781,and pending U.S. patent application Ser. No. 09/858,366, the disclosuresof which are hereby incorporated by reference for the purpose ofdescribing the details of a suitable radiation source. In a preferredembodiment the radiation source is made of iridium-192. However, othersuitable radioactive isotopes may be used such as palladium-103,iodine-125, cesium-131, rhenium-183, tungsten-181, thulium-170,ytterbium-169, terbium-161, dysprosium-159, gadolinium-153, samarium-145and xenon-127.

FIG. 2 shows a cross-sectional view of proximal portion 4 taken alongthe line II-II of FIG. 1. Balloon catheter 10 is provided with aninternal lumen 18 and an inflation lumen 25 that are together defined bya tube 19. Inflation lumen 25 is used for inflating balloon 14 ofballoon catheter 10. Inflation lumen 25 is provided with a barrier 26,such as a check valve, luer actuated valve, or other suitable means,which permits inflation of balloon 14 via inflation lumen 25, when in anopen position, and which retains fluid in balloon 14 when in a closedposition. Barrier 26 is also adapted to open to permit deflation ofballoon 14 at the end of the procedure in order to facilitate removal ofballoon catheter 10 from the surgical or body cavity. Balloon catheter10 is typically inflated by filling balloon 14 with a saline solution 9in order to inflate the balloon 14 once it is located in the cavity leftby the lumpectomy. Additional means for inflation may be used includingcontrast media for increased visibility, gels with a proper viscosity,as well as some types of soft, natural or synthetic rubbers, elastomericmaterials, small pellets, spheres, granules, powders, suspensions, gasgenerated from chemical reactions, and foams. Alternatively, the fluidinflation mechanism may include a syringe, a gel dispensing tube, orsimilar, conventional apparatus. The fluid inflation mechanism may beintegrated into the device, or it may be provided as a separate device.In a preferred embodiment, balloon 14 is inflated until it compresses atleast some of the tissue margins in the cavity.

Internal lumen 18 may be used for a variety of different purposes.Internal lumen 18 could be used for insertion of a guide wire orstiffening spine, for example, should these be required for a particularprocedure. Alternatively, a radiation source may be inserted viainternal lumen 18 as part of the treatment procedure. In an alternativeembodiment, inflation lumen 25 and internal lumen 18 are formed as asingle lumen, which may be used both for inflation of balloon 14 andinsertion of a radiation source or other device. In this embodiment,barrier 26 can be selected to allow a radiation source to pass throughwithout permitting back flow of fluid out of balloon 14, or, barrier 26can be advanced to a location closer to distal portion 6 such that itwould not be necessary to pass the radiation source through barrier 26in order to insert it into the single central lumen to deliver a dose ofradiation to the patient.

FIG. 3 shows a view of a breast after a lumpectomy has been performedwith balloon catheter 10 of FIGS. 1-2 inserted and inflated in thecavity left by the lumpectomy. From FIG. 3 it is apparent that thetissue boundary 28 that forms the cavity 29 left by the lumpectomy istypically non-uniform in shape. As a result, there is a need tocustomize the radiation dose delivered to the tissue to take intoaccount not only the non-uniform shape of the cavity, but also to ensurethat high-risk areas are sufficiently irradiated and that other healthytissue receives the least possible radiation dose to prevent or minimizeundesirable tissue damage. This is a very significant aspect of thepresent invention since prior art balloon catheters are generally onlyemployed in a small portion of procedures because of the significantdrawback that these devices offer either no ability, or at best, alimited ability to customize the radiation dose. As a result, doctorsoften opt for alternative treatment methods due to the risk ofsubstantial tissue damage and/or insufficient irradiation of thehigh-risk tissue that is encountered with prior art devices.

As shown in FIG. 3, proximal portion 4 of balloon catheter 10 is adaptedfor attachment to a device for filling the balloon, such as a syringe orother suitable pumping or transfer device. A syringe may be employed tofill balloon 14 with saline solution via inflation lumen 25, as shown inFIG. 5, and/or may be employed to after load one or more radioactivesources into source lumens 7 and/or internal lumen 18, as shown in FIG.5, particularly if the radioactive source is to be provided as a fluid.Any suitable, conventional afterloader may be employed with the deviceof the present invention, such as those that are commercially availablefrom Nucletron B.V. (Netherlands) and Varian Medical Systems, Inc. (PaloAlto, Calif.). Proximal portion 4 may be connected to an afterloaderusing a manifold connector similar to the manifold 30 depicted in FIG. 7below.

FIGS. 4-5 show an alternative embodiment of balloon catheter 10. In thisalternative embodiment, tube surface 16 of each tube 8 may be attachedto movable surface portion 2 of balloon 14 via a flexible attachment 22.The entire length of tube surface 16 may be attached to movable surfaceportion 2 from proximal portion 4 to distal portion 6 via flexibleattachment 22. Alternatively, tube surface 16 may be attached at one ormore attachment locations 20 located on movable surface portion 2 ofballoon 14 via flexible attachments 22. In FIG. 4, tube 8 is shownattached to movable surface portion 2 at two attachment locations 20 viaflexible attachments 22. Alternatively there could be more or lessattachment locations 20. Flexible attachments 22 may be fabricated froma material that is more flexible than the material employed to fabricatetubes 8. Tubes 8 may be made from a relatively rigid, crush-resistantmaterial that allows radial bending of tubes 8, as shown in the inflatedposition of FIG. 1, but tends to resist deformation of tubes 8 in amanner that prevents or minimizes deformation of source lumens 7. Sinceflexible attachments 22 are more flexible than tubes 8, flexibleattachments 22 will preferentially deform, e.g. by stretching, duringinflation of balloon 14, to thereby retain tubes 8 in close proximity tomovable surface portion 2, without causing substantial deformation oftubes 8 or source lumens 7. Tubes 8 may also incorporate directionalstrengthening or stiffening ribs in order to maintain radial positioningabout the surface of the movable surface portion.

Other suitable means for attaching tubes 8 to movable surface portion 2may also be employed. For example, tubes 8 may be formed integrally withmovable surface portion 2, though this embodiment is less preferredsince it may result in some deformation of tube 8 and hence sourcelumens 7 during inflation of balloon 14. Generally, the means forattaching tubes 8 to movable surface portion 2 allow some movement oftubes 8 relative to movable surface portion 2 such that deformation oftubes 8 thereby deforming source lumens 7, as a result of the inflationof balloon 14, is prevented or minimized. It is also within the scope ofthe present invention to apply a combination of flexible attachments 22and loops 12.

FIG. 6 shows another alternative embodiment wherein tubes 8 are notsecured to movable surface portion 2, but rather are only attached todistal and proximal portions 4, 6 of device 10. This embodiment providesthe most flexibility to tubes 8. In this embodiment, tubes 8 can befabricated from a relatively rigid material and are sized such thattubes 8 form a substantially tight fit with movable surface portion 2when balloon 14 is inflated, or incorporate directional stiffening ribs,in order to best locate tubes 8 at a predetermined location relative tothe longitudinal axis of balloon catheter 10. While it is preferable toprovide some additional stability to tubes 8 by securing tubes 8 tomovable surface portion 2 as described above, thereby ensuring thattubes 8 are always located substantially precisely at a predeterminedlocation relative to the longitudinal axis of balloon catheter 10, othermeans such as material selection or tube geometry and directionalstrengthening or stiffening ribs can be employed if desired.

FIG. 7 shows a front view of a manifold 30 which can form part of amanifold connector for connecting proximal portion 4 to an afterloader,or manifold 30 may be used to secure tubes 8 in position relative toproximal portion 4 of balloon catheter 10. Manifold 30 includes astructure 36 that defines passages 32 for receiving tubes 8 of theballoon catheter 10. Structure 36 also defines a central lumen 34through which can be passed, for example, a central tube 19 housing theinflation lumen 25 and internal lumen 18. Central lumen 34 canalternatively form an integral part of a combined inflation and internallumen, when the inflation and internal lumens are combined in a singlelumen, as described above. Manifold 30 can be employed to provide slackin tubes 8 as described above. For example, tubes 8 can be insertedthrough passages 32 and be allowed to freely move relative to manifold30 to provide the required slack. Alternatively, tubes 8 may be affixedto manifold 30 and manifold 30 may be movable relative to the device 10to provide the required slack in tubes 8. In another embodiment,manifold 30 is of sufficient thickness that passages 32 have sufficientlength to permit tubes 8 to slide some distance within passages 32,without disengaging from manifold 30, to provide the required slack intubes 8.

In one embodiment, a combination of the manifold 30, a plurality oftubes 8 and a distal attachment portion can be provided as a separatedevice that can later be combined with an inflatable balloon insertedthrough central lumen 34 in manifold 30. This would provide the abilityto use several different sized and/or shaped balloons provided with aplurality of external source lumens 7 formed by the plurality of tubes 8of various geometries as described above associated with manifold 30.

The brachytherapy device of the present invention has been describedabove with reference to several different embodiments of ballooncatheters 10. However, the device need not be a balloon catheter. Forexample, movable surface portion 2 can be provided by a movable orexpandable mechanical device, rather than being formed by an inflatableballoon. One suitable device is shown in FIGS. 8A-8D. As shown, thedevice can include a cylinder 100 having a proximal end 101 and beingformed from several distinct surface portions 102 that are attached toone another by, for example, hinges 104. The cylinder 100 is shown inthe unexpanded position in FIGS. 8A and 8C and in the expanded positionin FIG. 8B. Cylinder 100 is provided with an opening 106 that leads toan inner chamber defined by interior surfaces 108 into which a conicalexpander 110 may be inserted in order to expand the surface portions 102by contact between the outer surface 111 of conical expander 110 andinterior surfaces 108 as the conical expander is passed through opening106. Thus, the further that the conical expander 110 is inserted intothe inner chamber defined by interior surfaces 108, the greater theexpansion of the cylinder 100 since outer surface 111 of conicalexpander 110 will force the surface portions 102 outward by exertion offorce on interior surfaces 108 of cylinder 100. In this manner, themovable surface portions 102 of the device are actuated by a simplemechanical means, rather than by an inflatable balloon. This device canbe provided in a variety of shapes, other than cylindrical, to meet therequirements for a particular treatment. Other, conventional devicesthat provide movable surface portions can also be employed.

FIG. 9 shows a side view of expandable device 40 in an expanded stateand having a proximal portion 4 and a distal portion 6. Expandabledevice 40 includes an expandable structure 47 that forms an expandablesurface portion 2 and has an interior surface 3. Expandable device 40 isprovided with a plurality of attachment sleeves 42 which are secured toexpandable surface portion 2 of expandable structure 47. A plurality offlexible tubes 8 are secured to the expandable structure 47 viaattachment sleeves 42 in a manner whereby tubes 8 can slide withinattachment sleeves 42 to provide for relative movement between tubes 8and expandable structure 47.

Tubes 8 extend along the expandable surface portion 2 and terminate atdistal end 6 of expandable device 40. Tubes 8 may be provided with tubeend plugs 68 to prevent wire 41 or source 43 from exiting distal ends oftubes 8 during treatment and to prevent body fluids from enteringlumens. At distal end 6 of expandable device 40, there may be providedan attachment membrane 44 to which tubes 8 may be attached in anysuitable manner. Attachment membrane 44 is, in turn, secured to centraltube 19, shown in FIGS. 10A-12 to thereby provide structural support tothe distal ends of tubes 8.

In the embodiment of FIG. 9, expandable surface portion 2 is notexpanded by inflation, but is instead expanded by a mechanical expander.FIGS. 10A-12, discussed in detail below, show three differentembodiments of mechanical expanders for use with the expandable device40, each of which utilizes attachment sleeves 42 shown in FIG. 9.

FIGS. 10A-10B show a longitudinal cross-sectional view of one embodimentof an expandable device 40 as shown in FIG. 9. FIG. 10A shows theexpandable device 40 in the unexpanded state and FIG. 10B shows theexpandable device 40 in the expanded state. In this embodiment,attachment sleeves 42 are each secured to an equatorial tube spacingbelt 56 in any suitable manner, which tube spacing belt 56, in turn, issecured to expandable structure 47. Attachment sleeves 42 operate toboth secure tubes 8 to expandable structure 47 and to assist in guidingexpansion of expandable structure 47. Tube spacing belt 56 is secured toexpandable structure 47 in any suitable manner, such as by beingintegrally formed with expandable structure 47, or by being bonded,stitched, and fastened, etc. to expandable structure 47.

The mechanical expander of FIGS. 10A and 10B, includes four expanderrods 46 each of which is secured at the proximal end 59 thereof to amovable member such as a sliding sleeve 58 by any suitable means such asby affixation of the proximal ends of expander rods 46 in slots 60provided in sliding sleeve 58. Different numbers of expander rods 46 maybe employed. Typically, there will be one expander rod 46 for eachflexible tube 8. Distal ends 45 of expander rods 46 are secured to tubespacing belt 56 in any suitable manner such as by insertion intoflexible rod receptacles 48 formed integrally with tube spacing belt 56,as shown.

The mechanical expander of FIGS. 10A and 10B operates via themanipulation of sliding sleeve 58 located around central tube 19 in theproximal portion 4 of expandable device 40. During operation ofexpandable catheter 40, sliding sleeve 58 is moved relative to tube 19towards distal end 6 of expandable device 40. Moving sliding sleeve 58forces the proximal ends 59 of rods 46 to move towards the distal end 6of expandable device 40. Since distal ends 45 of rods 46 are fixed toexpandable structure 47, this will cause both expansion of expandablestructure 47 and bending of rods 46, as shown. Moving sliding sleeve 58back away from distal end 6 will reverse the process allowing rods 46 tostraighten by virtue of shape memory and allowing expandable structure47 to return to its unexpanded state. An optional binding ring 62 may beused to secure tubes 8 in an approximately cylindrical shape at theproximal portion 4 of the device 40.

Rod spacing lines 52 are an optional feature that may be used tomaintain a desired spacing between rods 46 and central tube 19. Rodspacing line 52 is attached to rods 46 at attachment points 54 and tocentral tube 19 for the purpose of maintaining a desired spacing betweenrods 46 and central tube 19 during expansion of expandable device 40.Rod spacing lines 52 are sufficiently flexible that lines 52 can bend tobe substantially parallel to central tube 19 when the device 40 is inthe unexpanded state. Alternatively, lines 52 may be rigid, in whichcase lines 52 should be hingedly or flexibly connected to central tube19 and rods 46 to allow for different angles between lines 52, centraltube 19 and rods 46 during expansion of expandable device 40.

Expandable device 40 may be used in the same manner as balloon catheter10 discussed above in order to treat the tissue in close proximity to abody or surgical cavity. After expansion of expandable device 40, anafterloader is used for inserting a source wire 41 or a source 43 intosource lumens 7 and/or internal lumen 18, within tubes 8 and 19respectively.

The expander shown in FIGS. 10A and 10B can expand the expandable device40 without the need for an inflation fluid. Thus, central tube 19 doesnot require an inflation lumen 25 as in the embodiments described abovewith respect to FIGS. 1-7. Also, the expandable structure 47 need not befluid tight and thus may take on a variety of alternative forms. Forexample, expandable structure 47 may be made from mesh, a perforatedsheet material or some other fluid permeable structure. However, it ispreferable that expandable structure 47 be fabricated in a manner thatprevents tissue surrounding the body or surgical cavity from penetratinginto expandable structure 47 since this may alter the dose profile inthe treatment area and/or complicates removal of the brachytherapydevice from the body or surgical cavity.

The two embodiments shown in FIG. 11 and FIG. 12 are alternativeembodiments of the expandable device 40 of FIG. 9 which use linkage arms80, rather than expander rods 46, in order to expand expandablestructure 47. Alternative expansion mechanisms using variousconventional forms of linkage arms are also possible. Linkage arms 80may be constructed of plastic, metal, carbon fibers, ceramics,super-elastics, shape memory materials, etc. Linkage arms 80 secure andguide tubes 8 during expansion of expandable structure 47 as a result ofthe attachment of linkage arms 80 to expandable structure 47 via pivotpoints 82 located at the locations of attachment sleeves 42. Linkagearms 80 are attached at their proximal ends 81 to slidable sleeve 58 viaadditional pivot points 83, and at their distal ends 85 to the distalportion 6 of expandable device 40 via additional pivot points 87. Pivotpoints 87 may be attached to central tube 19, as shown.

During operation of the embodiment shown in FIG. 11, sliding sleeve 58is moved towards distal end 6 of expandable device 40 from a firstposition to a second position. Sliding sleeve 58 is also connected totubes 8 via tube connecting member 84. Moving sliding sleeve 58 towardsdistal end 6 causes linkage arms 80 to pivot about pivot points 83, 87at pivot points 82. This causes pivot points 82 to move outwards to theposition shown in FIG. 11 to thereby expand the expandable structure 47.

In the embodiment shown in FIG. 12, rigid linkage arms 90 are attachedat one end to sliding sleeve 58 via pivot points 92 and are attached toexpandable structure 47 at the locations of attachment sleeves 42 viapivot points 93. Rigid linkage arms 90 secure and guide tubes 8 viaattachment sleeves 42 during the expansion of expandable structure 47.

During the operation of the embodiment shown in FIG. 12, sliding sleeve58 is moved towards distal end 6 of expandable device 40 from a firstposition to a second position. Moving sliding sleeve 58 towards distalend 6 causes rigid linkage arms 90 to pivot about pivot points 92, 93and thereby cause expansion of the expandable structure 47.

FIG. 13 shows a side view of an expandable device 64 where tubes 8 aresecured directly to outer surface 2 of expandable structure 47.Expandable device 64 is not inflated and is instead expanded with aninternal mechanical expander. FIGS. 14 and 15, discussed in detailbelow, show alternative embodiments of mechanical expanders for use withexpandable device 64 of FIG. 13.

FIG. 14 shows a cross-sectional view of one embodiment of an expanderfor the expandable device 64 shown in FIG. 13. The expander of FIG. 14includes a plurality of support rods 66 attached to a sliding sleeve 57via flexible attachments which may be flexible attachment receptacles70, as shown in FIG. 14. Flexible attachment receptacles 70 enable theproximal ends 65 of support rods 66 to be positioned at different anglesrelative to sliding sleeve 57 during the expansion process, whileremaining attached to sliding sleeve 57. Thus, in the unexpanded state,proximal ends 65 of support rods 66 may be substantially parallel to thelongitudinal axis of sliding sleeve 57. In the expanded state, shown inFIG. 14, proximal ends 65 of support rods 66 may be substantiallyperpendicular to the longitudinal axis of sliding sleeve 57. At distalend 6, support rods 66 are secured to a distal attachment fitting 78.Distal attachment fitting 78 includes a central tube attachment portion71 for supporting the distal end of central tube 19. Sliding sleeve 57may extend the length of central tube 19 in order to provide additionalsupport for expandable device 64 during the process of expansion.

Expansion is accomplished by moving sliding sleeve 57 towards distal end6 to cause support rods 66 to bend away from central tube 19, as shownin FIG. 14. Attached to expandable support rods 66 is a loose thin film,mesh or similar material, which forms expandable structure 47. Onceexpanded, binding ring 62 is used to secure sliding sleeve 57 and tubes8 in place for after-loading.

As shown in FIG. 14, optional secondary support rods 76 can be used inorder to provide additional structural support during the mechanicalexpansion. Secondary support rods 76 are attached to support rods 66 viaflexible attachment receptacles 74 and are secured to sliding sleeve 57via sleeve attachment portions 72. Flexible attachment receptacles 74enable secondary support rods 76 to flexibly move during the expansionof expandable structure 47. Sleeve attachment portions 72 act to secureand guide secondary support rods 72 so that they assist in providingstructural support to the support rods 66 so that a substantiallyspherical shape is achieved when expandable structure 47 is fullyexpanded.

The nature of the means for expansion in expandable device 64 shown inFIG. 14 permits expandable device 64 to be expanded without the need foran inflation fluid. This enables the usage of thin film membrane or amesh for the expandable structure 47 that may have reduced radiationattenuation properties and which need not be fluid tight. The mechanicalmeans used for expanding expandable device 64 means that central tube 19does not require an inflation lumen 25.

FIG. 15 shows a cross-sectional view of the expandable device 64 shownin FIG. 13. In the embodiment shown in FIG. 15, wire mesh 86, which canalso be a cage or slit tubing, is expanded from a cylindrical shape thatloosely conforms to the shape of central tube 19 to the spherical shapeshown in FIG. 15. Wire mesh 86 is attached to sliding sleeve 57 at itsproximal end 89 and to central tube 19 at its distal end. Wire mesh 86is constructed from a rigid plastic material or tempered metal,super-elastic, or a shape memory material that is flexible enough tobend, but rigid enough to be able to expand expandable structure 47 toform a substantially spherical shape. Alternatively, other geometriesmay be formed instead of a sphere depending on the needs of treatmentand/or cavity shape. Other shapes may include, for example, pear-shaped,elliptical, triangular, rectangular, irregular, or cylindrical.

In order to expand wire mesh 86 sliding sleeve 57 is moved towardsdistal end 6 of expandable device 64 to thereby exert pressure on theproximal end 89 of wire mesh 86 thereby causing wire mesh 86 to bendfrom a substantially straight configuration to the curved configurationshown in FIG. 15, thereby expanding expandable structure 47.

In the various embodiments discussed above, the movable member isdescribed as a slidable sleeve 57, 58 that moves towards the distal end6 of the expandable device 40, 64 from a first position to a secondposition in order to effectuate expansion of the expandable structure47. It is to be understood, however, that various other types of movablemembers may be employed in the context of the present invention. Forexample, similar results can be achieved by constructing the structuresuch that the movable member moves away from the distal end 6 ofexpandable device 40, 64 to effectuate expansion of expandable structure47. Also, different types of movable members may be employed, other thana slidable sleeve. For example, the movable member may be cylindricaldevice in an embodiment where no central tube is employed. The movablemember may also be in the form of a plurality of finger-like elements,each of which engages the proximal end of the support rod. Othervariations on the shape and structure of the movable member arepossible, so long as the movable member engages and exerts force on theproximal ends of the support rods to cause expansion of the expandablestructure. Likewise, the same device may naturally reside in theexpanded form and the movable structure may be employed to exert forceto return the shape of the device to a cylindrical form, for example.Referring now to FIGS. 16A-16B, there is shown another embodiment of adevice in accordance with the present invention that employs a shapememory material, such as nitinol. As shown in FIG. 16A, the device 120includes an inner tube 122 of shape memory material that has been heattreated to provide the desired shape memory, in this case ahemispherical shape as can be seen in FIG. 16B. Mounted on the outsideof inner tube 122 are a cap 133 and a plurality of semi-rigid orflexible tubes 124, each of which defines a source lumen 126 therethrough. The inner tube 122 and flexible tubes 124 are confined withinan outer tube 128 which may be made from a relatively rigid,biocompatible material such as titanium, stainless steel and otherconventional materials. Inner tube 122 may be formed by providing atube-shaped shape memory material, laser cutting the tube into aplurality of expandable arms 123 by cutting slots between the arms 123and heat treating the arms 123 to provide the desired shape, e.g.hemispherical in this case.

The device 120 is inserted into the surgical or body cavity in theunexpanded state shown in FIG. 16A. Once the device 120 is positioned inthe surgical or body cavity, outer tube 128 is retracted in the proximaldirection to the position shown in FIG. 16B, whereupon expandable arms123 expand to the hemispherical position shown in FIG. 16B by virtue oftheir shape memory characteristics. This causes tubes 124 to also take ahemispherical shape thereby positioning source lumens 126 closelyadjacent to the tissue to be treated. To allow tubes 124 to conform tothe shape of expandable arms 123 in the expanded position, slack may beprovided in tubes 124 at the proximal end in any of the mannersdescribed above with respect to other embodiments of the device of thepresent invention. Once the treatment is completed, the outer tube 128may be returned to its original position to return the device to theunexpanded state of FIG. 16A for retraction of the device from the bodyor surgical cavity. Optionally, inner tube 122 may define a centralsource lumen 127. The inner tube 122 may move in relation to theexpandable arms 123 during expansion of the device 120 causing thecentral source lumen 127 to axially shorten (relative to the sphericalportion) during expansion.

Expandable arms 123 may be covered by a film, mesh or balloon, notshown, located between expandable arms 123 and flexible tubes 124 tothereby provide a continuous movable surface portion, if desired for aparticular treatment.

FIGS. 17A-17D show alternative embodiments that are similar to theembodiments shown in FIGS. 16A-16B. The embodiment shown in FIGS.17A-17D includes finger grips 130, plunger 132, and anchoring cap 135.The expansion and contraction of the device is controlled by centralcontrol rod 131, shown in FIG. 16B. Central control rod 131 may define acentral lumen 127 which can be used as an additional source lumen duringthe treatment procedure. Central control rod 131 is attached toexpandable arms 123 via cap 133. Expandable arms 123 can be formed bypartially or wholly splitting a tube, for example, by laser cutting orother similar processes.

Once in the surgical cavity, outer tube 128, which functions like amanifold, is fixed and can temporarily be held in place using fingergrips 130. Outer tube 128 may also be provided with indicia identifyingone or more of the flexible tubes 124. Finger grips 130 can be removableor non-removable. Central control rod 131 is fixed to cap 133, but isfree to slide axially inside outer tube 128. To cause expansion ofexpandable arms 123, central control rod 131 is retracted in theproximal direction to the position shown in FIGS. 17C and 17D usingplunger 132. This moves the expandable arms 123 to the expanded positionshown in FIGS. 17C and 17D since the distal ends of expandable arms 123are captured in corresponding slots 141 in cap 133. Then control rod 131may be locked in position via a locking mechanism 138 facilitated byfriction, interference, rotation, an expanding collar, a thread, orother appropriate, conventional locking mechanism 138.

Optionally, a strain relief piece, not shown, with a predeterminedradius can be employed at the proximal and/or distal end of the deviceto keep flexible tubes 124 from kinking. Plunger 132 can be removable orpermanently affixed, and/or flexible or rigid. Plunger 132 can be in theform of a hand controlled rod, a kinematic mechanism, a pneumaticmechanism, or other device employing mechanical advantage that canoperate via being pushed, pulled, twisted, or bent.

Between inner tube 122 and flexible tubes 124 can be a membrane 134 madeof woven mesh or polymeric material to help sculpt tissue in the body orsurgical cavity. This membrane can be either elastic or flexible. Themembrane can also be either liquid-tight or breathable.

Finger grips 130 can also act as an anchoring cap or flap to restrictmotion of the device in and out of the entry site. The anchoring cap 135could also be a device that slides along the length of outer tube 128and is then fixed/locked to outer tube 128 and sutured to the skin.Anchoring cap 135, or, alternatively, a flap would restrict motion ofthe device in and out of the body entry site. This should reduce therate of infection. In an embodiment using a flap, the flap can be anextruded portion of the shaft.

The entire device can be placed in an outer sheath 136 while in theclosed position prior to insertion into the body or surgical cavity.Sheath 136 may be made of an expandable material, for example, elastic,a un-folding sheet (i.e. parachute-like: that opens by unfolding from atightly folded shape into a conformed shape), or some conformablestructure. The sheath 136 would act as a barrier between the device andthe body or surgical cavity to limit tissue ingrowth into the deviceand/or to act as a barrier to retain liquid inside the device. This mayreduce irritation to the surrounding skin during treatment andretraction of the device from the body or surgical cavity, as well asprovide a spacing structure to reduce the dose gradient in the treatmentzone. Sheath 136 may also be made of a bio-absorbable material thatcould remain in the cavity after the device is removed. The sheath maybe coated with an appropriate material to further reduce adhesion totissue and thereby minimize trauma.

FIGS. 18A and 18B show an alternative embodiment of expandable arms 123.In this embodiment, expandable arms 123 are hourglass-shaped. Expandablearms 123 of this embodiment, may be made by removing material from tube140. Tube 140 can be constructed of plastic or a shape memory materialsuch as nitinol. Hinge 137 forms a living hinge that enables expandablearms 123 to expand to form the spherical shape shown in FIG. 18B whenactuated by a movable member. In a preferred embodiment, there is amembrane stretched between each expandable arm 123. The membrane can bemade of woven mesh or polymeric material to help sculpt tissue in thebody or surgical cavity. This membrane can be either elastic orflexible. The membrane can also be either liquid-tight or breathable.

FIGS. 19A and 19B show an alternative embodiment of expandable arms 123.In this embodiment, expandable arms 123 may be made by makinglongitudinal slices 139 a tube 140 constructed of thin-walled materialsuch as metal. Hinge 137 is a living hinge that enables expandable arms123 to expand when actuated by a movable member. FIG. 19B shows across-sectional view of the device shown in FIG. 19A.

It is to be understood that in the above examples, non-spherical shapesmay also be employed throughout the embodiments and may be controlled asnecessary to fill the particular cavity in question. Sophisticatedcomputer programs exist for modeling radiation dosages and dose rates.Such computer programs are currently in use for brachytherapy treatmentplanning. It is contemplated the device of the present invention, whenused in combination with such a treatment planning tool, can providesignificant advantages over prior art devices. Specifically, thecomputer program can be employed to take into account a variety offactors that may affect the treatment such as the shape of the cavityleft by the lumpectomy, the distance to the tissue to be treated, thedesired depth of tissue irradiation, the existence of areas of healthyor different tissue for which it is desirable to reduce or minimize theradiation dose, etc. Using these parameters, it is possible to create acustomized treatment plan that can be carried out using the device ofthe present invention.

The design of the device of the present invention provides a number ofadvantageous features that can be exploited in the treatment planning.For example, the location of source lumens 7 on the outside of movablesurface portion 2 allows the positioning of the radioactive source inclose proximity to the treatment area with a minimal amount ofintervening structure and/or fluid reducing the shielding and/orattenuation of radiation by the structure of the device itself. Anothersignificant advantage of the device of the present invention is that itpresents a large number of different locations where the radioactivesource can be positioned to deliver the radiation dose. Not only can thesource be positioned in any of the source lumens or the internal orinflation lumen, but the source can also be positioned at any locationalong the length of any of these lumens. In addition, different lengthsources can be employed within the various lumens to alter the dosepattern. Moreover, sources of different activities can be usedsimultaneously or sequentially in one or more of the lumens to furthercustomize the treatment. In this manner, far more precise dosing can beprovided than in prior art brachytherapy devices. As a result, thedevice of the present invention will be useful in a significantly largernumber of procedures, due to the flexibility that it provides in dosingthe patient.

The device of the present invention can be customized in various waysfor specific patients or treatments. For example, the device may be madein different lengths to accommodate different depths of body or surgicalcavities. In addition, the device may be fabricated with different sizesand/or shapes of movable surface portions to accommodate different sizedbody or surgical cavities. Also, in specific cases it may be possible ordesirable to use one or more radiation sources outside the expandablesurface portion to provide additional tailoring of the dose profiledelivered by the device.

The device of the present invention offers several advantages in use.One important advantage is that it permits a very high degree of dosecustomization for particular treatment plans. Another advantage is thatthe device of the present invention can be implanted for lengthy periodswithout causing a significant disruption in the patient's life tothereby permit treatments over a period of days or even weeks. Thisadvantage is realized because the proximal portion of the device thatextends out of the body or surgical cavity can easily be secured andhidden, for example, under the armpit of a breast cancer patient, whilethe device is implanted. Also, the present invention provides theability to easily customize the length of the device for body orsurgical cavities located at different depths in the body since it ispossible to cut the tubes to a desired length for use.

The method for using a brachytherapy device in accordance with thepresent invention for interstitial treatment of breast cancer will nowbe discussed. First a lumpectomy is performed on a patient's breast. Asurgeon makes a small incision over or near the breast tumor and excisesthe lump or abnormality along with a margin of appropriate thickness ofnormal surrounding breast tissue. After the lumpectomy has beenperformed the patient may now undergo radiation treatment using abrachytherapy device in accordance with the present invention. Instandard radiation treatment after a lumpectomy the treatment runsroughly six weeks for standard external beam radiation therapy.Utilizing the device of the present invention, the treatment can usuallybe shortened to, for example, twice daily for five days. The treatmenthyperfractionation of 3.4 Gy b.i.d. (twice daily) for five days (with atleast six hours between each fraction) is a clinically derived schedulefor accelerated partial breast irradiation. Alternatively, the device ofthe present invention may be used to provide a boost radiation treatmentto the lumpectomy site typically following external beam radiation.

FIG. 20 shows a schematic representation of one method for using abrachytherapy device in accordance with the present invention. At step502, at least the portion of the brachytherapy device of the invention,including the movable surface portion 2, is inserted via a surgicalincision made in the breast into the cavity in the breast that remainsafter a lumpectomy. At step 504 movable surface portions 2 are movedwithin the cavity to position source lumens 7 closer to tissue boundary28.

At step 506 one or more radioactive sources are loaded into one or morelumens 7, 18. Loading may be dictated, for example, by a predeterminedtreatment plan. Step 506 can involve one or more sub steps, depending onthe complexity of the treatment plan. Also, the same or differentsources may be inserted into different tubes 8, at different locationsalong the lengths of the tubes 8 and/or for different durations, asexplained above. At step 508 the one or more radioactive source(s) areremoved from lumens 7, 18 to conclude the treatment. At step 510, themovable surface portions 2 are returned to their original position andat step 512 the brachytherapy device is retracted from the body orsurgical cavity. Steps 502-512 can be repeated as needed. The method ofthe present invention may further include an additional step ofpreparing a treatment plan to be followed in step 506, if desired.

Although use of a brachytherapy device of the present invention has beendescribed in the context of breast cancer brachytherapy, it is to beunderstood that the various devices of the present invention can beemployed in any type of interstitial brachytherapy wherein a device isinserted into a surgical cavity. The device of the present invention mayalso be employed in intra-cavital brachytherapy in an existing bodycavity. For example, the devices of the present invention may beemployed for inter-uterine brachytherapy, esophageal brachytherapy,nasal-pharyngeal brachytherapy, rectal brachytherapy, or for treatmentafter removal of a tumor, cyst, polyp or other mass, thereby creating asurgical cavity.

Although the devices and methods of the present invention have beendescribed with reference to breast cancer brachytherapy, it is to beunderstood that these devices are applicable for other types ofbrachytherapy treatment involving insertion of the brachytherapy deviceinto a body cavity or a surgical cavity created by a surgical procedure.These devices or methods may also be employed for the delivery ofvarious drug therapies or diagnostic agents desired for the treatment ofvarious other disease states.

It is to be understood that even though numerous characteristics andadvantages of the present invention have been set forth in the foregoingdescription, together with details of the structure and function of theinvention, the disclosure is illustrative only, and changes may be madein detail, especially in matters of shape, size and arrangement of partswithin the principles of the invention to the full extent indicated bythe broad general meaning of the terms in which the appended claims areexpressed.

1. A device for use in brachytherapy comprising: a proximal portion; aplurality of source lumen tubes comprising proximal ends and distalends, the distal ends coupled together, the source lumen tubes definingan expandable structure proximate to the distal ends, said source lumentubes extending a sufficient distance into the proximal portion of saiddevice such that said proximal ends of said source lumen tubes arelocated outside a body when said device is positioned for brachytherapyin a body cavity of said body, and each said source lumen tube definingat least one source lumen that extends from said distal end through theexpandable structure to said proximal portion of said device forpositioning a source of radiation therein; a ring which surrounds atleast a portion of said source lumen tubes; a movable member operativelyassociated with said distal ends of said source lumen tubes such thatmovement of said movable member moves said expandable structure from afirst position to a second treatment position that is at a greaterradial distance from a longitudinal axis of the device than a radialdistance from said expandable structure to the longitudinal axis of thedevice when said expandable structure is in said first position, saidmovable member defining a central lumen extending at least from alocation within said expandable structure to a sufficient distance intothe proximal portion of said device to allow insertion of a radiationsource into said central lumen when said device is positioned forbrachytherapy; and a kinematic mechanism operatively associated withsaid movable member such that actuation of said kinematic mechanismcauses movement of said movable member to enable expansion of saidexpandable structure.
 2. The device of claim 1, wherein expansion ofsaid expandable structure is caused by movement of said movable memberin a distal direction relative to said ring.
 3. The device of claim 1,wherein said kinematic mechanism is operable by one of pushing, pulling,twisting or bending.
 4. The device of claim 3, wherein said kinematicmechanism is operable by twisting.
 5. The device of claim 4, whereinsaid kinematic mechanism employs a mechanical advantage.
 6. The deviceof claim 1, wherein said kinematic mechanism is removable from saiddevice.
 7. The device of claim 1, comprising a locking mechanism to locksaid movable member in position.
 8. The device of claim 7, wherein saidlocking mechanism operates by a methodology selected from friction,interference, rotation, expansion of a collar and threaded engagement.9. The device of claim 8, wherein said locking mechanism operates bythreaded engagement.
 10. The device of claim 1, wherein said movablemember is a rod.
 11. The device of claim 10, wherein said movable memberis a control rod that moves axially relative to said ring substantiallyalong a longitudinal axis of said device.
 12. The device of claim 1,wherein said movable member is a sleeve.
 13. The device of claim 1,wherein said movable member is cylindrical.
 14. The device of claim 1,comprising at least four source lumen tubes.
 15. The device of claim 1,wherein a distal end of said movable member is coupled to said distalends of said source lumen tubes.
 16. A brachytherapy system comprising adevice as claimed in claim 1 and at least one source of radiation forinsertion into said at least one source lumen, said source of radiationbeing selected from the group consisting of iridium-192, palladium-103,iodine-125, cesium-131, rhenium-183, tungsten-181, thulium-170,ytterbium-169, terbium-161, dysprosium-159, gadolinium-153, samarium-145and xenon-127.
 17. The device of claim 1, wherein movement of saidexpandable structure to said second treatment position positions saidsource lumen tubes at predetermined locations relative to a longitudinalaxis of the device to provide accurate positioning of radiation sourceslocated within said source lumen tubes for brachytherapy treatment. 18.The device of claim 1, wherein the source lumens are enclosed to preventfluids from entering the source lumens when the device is positioned forbrachytherapy treatment.